Pipette dryer



July 5, 1966 A. N. SWANSON PIPETTE DRYER 2 Sheets-Sheet 1 1 Filed April 22., 1963 INVENTOR. Are-mun. H. Swmsou A TTORMEVS July 5, 1966 A. N. SWANSON 30 &9

2 Sheets-Sheet 2 INVENTOR. ARTHUR H. Qwmsou MM/m ATTORNEYS United States Patent M 3,258,850 PIPE'ITE DRYER Arthur N. Swanson, South Greenfield, Mo.

' (Rte. 2, Box 1C, Miller, M0.) Filed Apr. 22, 1963, Ser. No. 274,436 4 Claims. ((31.34-104) This invention relates to laboratory glassware drying equipment, and more particularlyv to pipette drying apparatus.

Pipettes and certain other types of laboratory glasswere usually are cleaned and washed after use and must be thoroughly dried before reuse. This is often diflicult, particularly with respect to pipettes, because they are very fragile and consist chiefly of elongated tubes having extremely narrow passageways from which liquids do not drain with ease. Pipettes heretofore usually have been dried in ovens, however this required extremely long periods of time and deposits such as water marks were often left therewithin due to improper drainage. Also, the pipettes were to hot to handle for a considerable period after the drying step was completed. 7

The principal objects of the present invention are: to provide pipette drying apparatus which promotes rapid drainage and drying by maintaining the pipettes in a vertical position and forcing heated air in a downdraft therepast; to provide such drying apparatus which filters the air forming the downdraft so as to avoid the disposition of dust or other foreign matter within the pipettes; to provide such drying equipment which permits .e-asy loading and unloading and which may be placed on an elevated shelf so as to avoid occupying valuable floor space; to provide such apparatus which does not overheat contents whereby the pipettes may be handled and used immediately upon removal from the apparatus; and to provide such a pipette dryer which is simple and rugged in construction and highly efiicient in use.

Other objects and advantages of this invention will become apparent from the following description taken in connection with the accompanying drawings whereinlare set forth by way of illustration and example certain embodiments of this invention.

FIG. 1 is a perspective view of a pipette dryer embodying this invention shown assembled and ready for use.

FIG. 2 is a fragmentary perspective exploded view of the pipette dryer with a pipette-receiving barrel telescoped downwardly from the dryer stand.

FIG. 3 is a vertical cross-sectional view through the pipette dryer particularly showing the drying air flow path therethrough.

FIG. 4 is a fragmentary cross-sectional view through the dryer taken on the line 44, FIG. 3., particularly showing a squirrel cage blower. 7

FIG. 5 is a cross-sectional view through the dryer taken on the line 55, FIG. 3, particularly showing wall insulation and a bottom screen on the pipette-receiving barrel.

Referring to the drawings in more detail;

The reference numeral 1 generally indicates a pipette dryer embodying this invention. The dryer 1 comprises a vertically extending container 2 having a cylindrical .outside wall 3 and a cylindrical inside wall 4 spaced coaxially inwardly from the outside wall. The container inside wall 4 forms an interior vertical cylindrical receiving passageway 5 open at the top and bottom 7 thereof. An insulating material 8 such as glass fiber blanket is supported between the container walls 3 and 4 to prevent .excessive heat loss from the passageway 5 and reduce noise transmission.

The container outside wall '3 extends upwardly past the insulating material 8 and the top 9 of the inside wall 4 forming an upper mounting sleeve or portion 10. An

electrical resistance heating coil assembly 11, preferably in the nature of 1000 watts, is supported by suitable suspension members 12 on the upper mounting portion 10 and has heating coils 13 extending across the receiving passageway 5 near the top 6 thereof.

Latch anchors 14 are fixed on the exterior of the upper mounting portion 10 and extends radially outwardly therefrom. Suitable crossed brace members 15 rigidly support the cylindrical walls 3 and 4 with respect to each other without interfering with .air flow discussed below.

A housing broadly designated 16 has a vertically ex tending cylindrical wall 17 of substantially the same diameter as the outsdie wall 3 and forms a cylindrical chamber 18 having an open upper end 19 and open lower end 20. The housing 16 includes a downwardly extending annular flange 21 fixed at the lower end of the housing wall 17 and telescopically receiving the upper mounting portion 10 of the outside wall 3 for aligning the housing 16 with the container passageway 5. A resilient annular gasket 22 is located between the flange 21 and the upper mounting portion 10 to prevent leakage of air past the junction between the wall 17 and the wall 3. Quick release latch members 23 are fixed to the flange 21 and respectively engage the latch anchors 14 for removably securing the housing 16 on the container 2.

The housing 16 has an electric motor 24 therewithin mounted .on brackets 25 secured to the wall 17 and extending inwardly thereof. The motor 24 has a diameter substantially smaller than the inside diameter of the housing chamber 18 forming air flow passageways 26 therebetween. The motor 24 includes an upwardly extending shaft 27 coaxially rotatable within the housing chamber 16 and a squirrel cage blower 28 is fixed to the shaft 27 and rotatable within the chamber 18 above the motor. The blower 28 has an outside diameter smaller than the inside diameter of the chamber 18, permitting air expelled outwardly from the blower to impinge against the wall 17 where it is directed downwardly through the air flow passageways 26. A baflle ring 29 is secured to the wall 17 and extends over the upper peripheral edges of the blower 28 to prevent air from moving upwardly rather than downward with respect to the housing 16. The baflle ring 29, however, presents no obstruction for the intake 30 of the blower 28.

A ring member 31 is fixed to the housing wall 17 slightly spaced above the bathe ring 29 and has a lip 32 extending inwardly into the chamber 18. A filter pad 33 has the peripheral edges thereof resting on the lip 32 and the pad 33 closes the upper end 19 of the housing 16. A cap 34 of conical shape has a lower lip 35 received over the housing 16 at the upper end 19 and the cap 34 traps a screen 36 against the filter pad 33 for maintaining said filter pad in proper position. The cap 34 has a central bore or opening 37 at the upper end thereof forming an intake permitting air to pass downwardly through the screen 36 and filter pad 33 into the blower intake 30. A shield 38 is spaced closely beneath the motor 24 and is perforated, permitting air flow therepast but protect ing the motor against excessive heat radiation from the heating coils 13. The shield 33 also protects the motor from physical damage when the housing 16 is removed from the container 2 for maintenance.

The motor 24 has an electric power-receiving cord 39 which is directed to a plug member 40 communicating through and mounted on the outside surface of the housing 16. The plug member 40 includes a control switch 41 for introducing power into the pipette dryer and a suitable power input cord 42 directs power to the plug member 40 in a conventional manner. The plug member 40 has a pair of leads 43 connected thereto in parallel with the cord 39, which leads extend through an opening 44 in the lower edge of the housing 16, termimating in a plug 45 which is removably connected to pron-g contacts or terminals 46 of the heating coils 13 on the exterior of the container 2. Thus, when it is desired to remove the housing 16 from the container 2, the housing may be electrically disconnected as well as physically by the removal of the plug 45 from the plug contacts 46 along with release of the latches 23. It is noted that the actuation of the switch 41 simultaneously powers the motor and the heating coils for urging air through the filter pad 33, past the motor 24, past heating contact with the coils 13 and into the passageway 5.

An elongated vertical cylindrical pipette-holding sleeve or barrel 47 is open at the upper end 48 and lower end 49 thereof and is telescopically receivable upwardly into the passageway 5. The barrel 47 has a pipette-retaining screen 50 extending across the lower end 49 and secured in position by means of a ring clamp 51. The screen 50 is preferably approximately 40-mesh and the respective pipettes 52 are placed with the points 53 thereof down in contact with the screen 50 for ease of draining under pressure exerted by the air flow against the upper ends 54 and past the points 53.

A support flange 55 is secured to and extends upwardly and outwardly from the barrel lower end 49 for a purpose discussed below. A frusto-conical hollow annular perforated stand 56 having an upwardly open top portion 57 and a downwardly open bottom portion 58 is secured to the lower end of the container outside wall 3 and extends downwardly and outwardly therefrom. Quick release latch members 59 are secured to the container outside wall 3 and have hook portions extending partially through upper perforations 60 in the stand 56 and selectively engaging the periphery of the barrel support flange 55 for retaining the barrel 47 in the passageway with the pipette screen 50 spaced above the bottom portion 7 58 of the stand. Upon release of the latch members 59,

the barrel 47 and the contents thereof are free to drop downwardly through the open bot-tom portion 58 of the stand. Additional perforations 61 extend through the stand 56 at the bottom portion 58 to allow the free flow of air past the screen 50 in case the pipette dryer is standing on an uninterrupted surface.

In operation, the pipette dryer is preferably placed on an elevated shelf 62 for ease of loading and to avoid occupying valuable floor space. The shelf 62 preferably contains an access indentation or opening 63 smaller than the diameter of the stand 56 at the bottom portion 58 thereof but larger than the diameter of the support flange 55. The pipettes 52 are placed in the barrel 47 with the points extending downwardly and being supported by the screen 50. The barrel 47 is then urged upwardly through the opening 63 into the passageway 5 and the latch members 59 engaged with the support flange 55 to maintain the barrel 47 tightly secured in the heated air flow path which subsequently moves downwardly though the screen 50 and past the opening 63 and/or perforations 61.

Suitable dimensions for the pipette dryer have been found to be approximately 27 inches in height, 11 inches in maximum base width and a pipette-containing barrel diameter of approximately 6 inches. Using a 1000 watt heating coil and a blower motor of suitable power, it has been found that 125 pipettes can be dried absolutely, looking clean and clear in less than 20 minutes. This is a great decrease in the time heretofore required and the filtered drying air reduces the probability of dust or foreign particle inclusion in the pipettes during drying. By releasing the latch members 59 after the drying cycle is completed, the barrel is removed downwardly. The pipettes are not too hot to be immediately handled and used, unlike pipettes dried by the usual oven methods.

It is to be understood that while one form of this invention has been illustrated and described, it is not to be limited to the specific form or arrangement of parts herein described and shown except insofar as such limitations are included in the claims.

What I claim and desire to secure by Letters Patent is 1. A pipette dryer comprising; a vertically extending container having a wall forming a vertical receiving passageway open at the top and bottom thereof, said container wall having an upper mounting portion, an electrical resistance heating coil assembly supported on said upper mounting portion and having heating coils extending across said receiving passageway at the top thereof, blower means mounted on said container adjacent said heating coils for blowing air past said heating coils and downwardly into said passageway, an elongated vertical pipette-holding barrel open at the upper and lower ends thereof, said barrel being telescopically received upwardly into said passageway, pipette-retaining means adjacent the barrel lower end for engaging and supporting pipettes longitudinally of said barrel and permitting air passage therepast, support means on said container wall and extending downwardly from said container passageway bottom and terminating in bottom edges for resting on a supporting surface, and means carried by said container and selectively engaging said barrel for retaining said barrel in said passageway with the pipette-retaining means spaced above the bottom edges of said support means, said barrel being movable downwardly past said support means upon release of said barrel-retaining means.

2. A pipette dryer comprising; a vertically extending container having a cylindrical outside wall and a cylindrical inside Wall spaced inwardly from said outside wall, said container inside wall forming a vertical cylindrical receiving passageway open at the top and bottom thereof, insulation material supported between said container walls, said container outside wall extending upwardly from said insulation and inside walls forming an upper mounting portion, an electrical resistance heating coil assembly supported on said upper mounting portion and having heating coils extending across said receiving passageway at the top theerof, a housing forming a cylindrical chamber having an open upper and lower end, means removably securing said housing on said container with the open lower end of the housing aligned therewith, blower means in the housing chamber, a ring member fixed to said housing and extending into said cylindrical chamber, a filter pad resting on said ring member adjacent the open upper end of the housing, a screen in said housing at said upper open end holding said filter pad in position so that air moves through said screen and filter pad to the blower and is discharged downwardly over the heating coil and into said container, an elongated vertical cylindrical pipette-holding barrel open at the upper and lower ends thereof, said barrel being telescopically received upwardly into said passageway and having a pipette-retaining screen extending across said barrel lower end, support means secured to a bottom portion of said container and extending downwardly and outwardly therefrom and having bottom edges for rest ing on a support surface, latch means on said container and selectively engaging said barrel for retaining said barrel in said passageway with said pipette screen spaced above the bottom edges of said suport means, said barrel being removable downwardly past said support means upon release of said latch means.

3. A pipette dryer comprising; a vertically extending container having a cylindrical wall forming a vertical cylindrical receiving passageway open at the top and bottom thereof, said container wall having an upper mounting portion, an electrical resistance heating coil assembly supported on said upper mounting portion and having heating coils extending across said receiving passageway at the top thereof, blower means mounted on said container adjacent said heating coils for blowing air past said heating coils and downwardly into said passageway, an elongated vertical cylindrical pipette-holding barrel open at the upper and lower ends thereof, said barrel being telescopically received upwardly into said passageway and having a pipette-retaining screen extending across said barrel lower end for longitudinally supporting pipettes in said barrel but permitting air passage therepast, a support flange secured to said barrel lower end, a hollow perforated stand having an open top and bottom, said stand being secured to said container wall and extending downwardly from said container passageway bottom, latch members secured to said container Wall and extending partially through said stand and selectively engaging said barrel support flange for retaining said barrel in said passageway with said pipette screen spaced above the bottom of said stand, said barrel being removable downwardly past said stand upon release of said last-named latch members.

4. The apparatus as set forth in claim 3 wherein said blower means includes; a housing having a vertically extending cylindrical wall of substantially the same inside diameter as said container Wall and forming a cylindrical chamber having an open upper and lower end, said housing including a flange fixed to the lower end of said housing wall and removably receiving said upper mounting portion for aligning said housing with said container, latch members fixed to said housing flange and cooperating with said container wall for removably securing said housing on said container, said housing having an electric motor mounted on said housing wall within said housing chamber, said motor being of smaller diameter than said chamber and including an upwardly extending shaft rotatable coaxia-lly therewithin, a blower fixed to said motor shaft and rotatable within said housing chamber above said motor, a support member fixed to said housing wall above said blower, a filter pad resting on said support member and closing said receiving passageway at the top thereof, a cap received over said housing at said upper end and having means thereon trapping said filter pad in position on said support member, said cap having a central bore forming an intake opening for said blower, and electric current transmitting means for simultaneously operating said motor and said heating coil assembly.

References Cited by the Examiner UNITED STATES PATENTS 777,504 12/1904 Gathmann 34-218 X 1,760,997 6/1930 Shelton 21939.13 1,777,493 10/1930 Jadin et a1. 34--197 X 2,081,034 5/1937 Carter 21939.13 X 2,441,062 5/ 1948 Elsebusch 34106 2,479,706 8/1949 Williams 34-233 X 2,546,385 3/1951 Christina. 2,721,395 10/1955 Walker 34-90 2,846,777 8/ 1958 Collins 3490 2,966,573 12/1960 Hansen 219-39.17 X 3,103,688 9/1963 Rose 15-288 FOREIGN PATENTS 541,614 10/1955 Belgium.

FREDERICK L. MATTESON, JR., Primary Examiner.

NORMAN YUDKOFF, Examiner.

J. SOFER, Assistant Examiner. 

1. A PIPETTE DRYER COMPRISING; A VERTICALLY EXTENDING CONTAINER HAVING A WALL FORMING A VERTICAL RECEIVING PASSAGEWAY OPEN AT THE TOP AND BOTTOM THEREOF, SAID CONTAINER WALL HAVING AN UPPER MOUNTING PORTION, AN ELECTRICAL RESISTANCE HEATING COIL ASSEMBLY SUPPORTED ON SAID UPPER MOUNTING PORTION AND HAVING HEATING COILS EXTENDING ACROSS SAID RECEIVING PASSAGEWAY AT THE TOP THEREOF, BLOWER MEANS MOUNTED ON SAID CONTAINER ADJACENT SAID HEATING COILS BLOWING AIR PAST SAID HEATING COILS AND DOWNWARDLY INTO SAID PASSAGEWAY, AN ELONGATED VERTICAL PIPETTE-HOLDING BARREL OPEN AT THE UPPER AND LOWER ENDS THEREOF, SAID BARREL BEING TELESCOPICALLY RECEIVED UPWARDLY INTO SAID PASSAGEWAY, PIPETTE-RETAINING MEANS ADJACENT THE BARREL LOWER END FOR ENGAGING AND SUPPORTING PIPETTES LONGITUDINALLY OF SAID BARREL AND PERMITTING AIR PASSAGE THEREPAST, SUPPORT MEANS ON SAID CONTAINER WALL AND EXTENDING DOWNWARDLY FROM SAID CONTAINER PASSAGEWAY BOTTOM AND TERMINATING IN BOTTOM EDGES FOR RESTING ON A SUPPORTING SURFACE, AND MEANS CARRIED BY SAID CONTAINER AND SELECTIVELY ENGAGING SAID BARREL FOR RETAINING SAID BARREL IN SAID PASSAGEWAY WITH THE PIPETTE-RETAINING MEANS SPACED ABOVE THE BOTTOM EDGES OF SAID SUPPORT MEANS, SAID BARREL BEING MOVABLE DONWARDLY PAST SAID SUPPORT MEANS UPON RELEASE OF SAID BARREL-RETAINING MEANS. 